Storage drive heat sink mounting structure

ABSTRACT

A heat sink can be used as part of a storage drive to perform multiple functions, both structural and thermodynamic. It can be used as a heat dissipating element and it can be used as the key mechanical mounting structure for storage drives, such as hard disk drives (HDD), and any circuit boards.

BACKGROUND

A hard disk drive (HDD) is a storage drive used for storing andretrieving digital information. A HDD generally has one or more rapidlyrotating disks with a magnetic head arranged on a moving actuator arm toread and write data to the disk surface. A typical disk is spun atspeeds varying anywhere from 4,200 rpm in energy-efficient portabledevices, to 15,000 rpm for high performance servers. Other disks mayspin at 1,200 rpm, 3,600 rpm, or in the range of 5,400 rpm to 7,200 rpm,though any range of speeds could be used.

Due to the extremely close spacing between the magnetic head and thespinning disk surface, HDDs are vulnerable to being damaged by a headcrash—a failure of the disk in which the head scrapes across the plattersurface, often grinding away the thin magnetic film and causing dataloss. Head crashes can be caused by, among other things, electronicfailure, a sudden power failure, physical shock, contamination of thedrive's internal enclosure, wear and tear, corrosion, or poorlymanufactured disks and heads. In addition, the high speed disks cangenerate large amounts of heat that needs to be dissipated.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are depicted in the accompanying drawings forillustrative purposes, and should in no way be interpreted as limitingthe scope of the inventions.

FIG. 1 shows a storage drive.

FIG. 2 is a cross-sectional view of the storage drive taken along lineA-A of FIG. 1.

FIG. 3 is a partially exploded view of the storage drive.

FIG. 4 shows a subassembly of the storage drive with drive mountingsystem.

FIG. 4A illustrates an exploded view of the subassembly of FIG. 4.

FIGS. 5A and 5B show perspective views of a heat sink.

FIG. 6 is a detail cross-sectional view of a storage drive.

FIG. 7 shows another embodiment of heat sink.

DETAILED DESCRIPTION

One way to protect a HDD from a head crash is to provide protection fromphysical shock. For example, the hard drive may be isolated from anenclosure and/or other components by shock mounts that are positionedbetween the hard drive and the enclosure. Shock mounts are oftenattached directly to the hard drive and the hard drive is effectivelysuspended within the enclosure by way of the shock mounts. Further, fansare often used to cool the device. These fans are often one of thelargest consumers of power in the device.

A storage drive 100 is illustrated in FIG. 1. The storage drive 100 canprovide digital storage through a physical drive, such as a hard diskdrive (HDD) 20. A drive mounting system 10 (FIG. 2) that can provideheat dissipation and/or shock absorption in a storage drive will now bedescribed. As can also be seen, the drive mounting system 10 can providea space efficient mounting system for a space efficient enclosure of thestorage drive. It will be understood that the concepts described hereincan be employed for other uses and with other devices, including, butnot limited to, other types of storage drives, whether internal orexternal, computers, and all types of sensitive electronic devices. Forexample, the shock absorbing system may also be used with solid-statedrives (SSD) and solid-state hybrid drives (SSHD).

A drive mounting system 10 can utilize one or more multipurpose heatsinks 50 as a mounting structure with provision to adapt shock mounts.Further the drive mounting system 10 can provide a passively orsemi-passively cooled enclosure for a storage device. For example, thedrive mounting system 10 can provide a semi-passively cooled enclosurefor a Nano-RAID external storage device, especially a THUNDERBOLTNano-RAID device.

RAID devices are typically used to provide redundant storage forsensitive data. Conventional RAID devices are powered by a wall outlet,and in many instances, a battery backup. Unfortunately, this limitsconventional RAID devices from a wide variety of applications and usecases, such as mobile uses, and field applications.

Typically, bus powered devices have strict power budgets due to thelimitations of the power signal that can be delivered over a businterface, such as a USB or THUNDERBOLT interface. One of the largestconsumers of power is a fan to cool the device. A drive mounting system10 can be used to provide a passively or semi-passively cooled system.In some embodiments, a drive mounting system 10 can be part of aNano-RAID enclosure with natural convection cooling and shock/vibrationisolation, among other things.

Turning now to FIGS. 1-3, some of the features of the illustratedstorage drive 100 will be described. The storage drive 100 is shown withfirst 30 and second 40 mating members that combine to form an enclosure.FIGS. 1 and 3 show the storage drive 100 in an assembled and unassembledcondition, respectively. One or more hard disk drives (HDD) 20 can bepositioned within the enclosure (FIG. 2), as can one or more printedcircuit boards (PCB) 12. The cross section of FIG. 2 shows two HDDswithin the enclosure. One or more fans 14 (FIG. 3) may also be included,as can a number of shock absorbers 16.

An electrical connector 18 is also illustrated as part of the storagedrive 100. The electrical connector 18 can be any number of differentconnector types such as USB, THUNDERBOLT, optical, serial, parallel,FIREWIRE, etc. The illustrated connector is a compact design that allowsthe cable to wrap around the enclosure (first mating member 30) with theconnector end 19 connecting to and being stored within another part ofthe electrical connector 18.

One or more heat sinks 50 can be used as a frame or mounting structurefor mounting one or more storage drives 20 within the enclosure as bestseen in FIG. 2. The heat sinks and drives can form a subassembly 22(FIG. 3). The subassembly 22 can be suspended within the enclosure byone or more shock absorbers 16. As will be understood in FIG. 3, screwscan pass through the first mating member 30 of the enclosure, the shockabsorbers 16 and then threadingly engage the second mating member 40.Other attachment methods can also be used.

Looking now to FIGS. 4-4A, the subassembly 22 of the storage drive witha drive mounting system 10 is shown in assembled and unassembledconditions respectively. In some embodiments, a drive mounting system 10can include one or more heat sinks and one or more disk drives or othertypes of drives. In the illustrated embodiment, the storage drive has adrive mounting system 10 with two heat sinks 50 and two HDDs 20. Inanother embodiment, a single heat sink can be used with two or moreHDDs. The various embodiments of drive mounting system 10 may alsoinclude one or more shock absorbers 16.

As illustrated, four shock absorbers 16 are included, one on each cornerof the subassembly 22. The drives 20 are shown directly attached to theheat sinks 50. The shock absorbers 16 are directly connected to the heatsinks. When assembled, the shock absorbers 16 are in contact with theenclosure and suspend both the heat sinks and the drives within theenclosure. A sway space (FIG. 2) can be maintained around thesubassembly 22, with the primary exception of the shock absorbers, suchthat the heat sinks and drives are not in contact with the enclosure.The sway space can also help minimize the possibility of the heat sinksand drives contacting the enclosure during an impact or other shock.

In some embodiments that shock absorbers 16 can slide on to heat sinks50. The shock absorbers can be rubberized or elastic end caps to theheat sink 50. The shock absorbers 16 can also attach to the heat sink inany number of other ways.

The drive mounting system 10 can further include additional featuressuch one or more PCBs 12 and one or more fans 14 (FIGS. 4-4A). In theillustrated embodiment, two PCBs and one fan are included. It will beunderstood that some or all of the PCBs and fans can be positioned inthe enclosure separately from the drive mounting system 10. As has beenmentioned, some embodiments are passive cooling systems and do notinclude a fan.

In some embodiments, the heat sink 50 of the drive mounting system 10can be thermally connected to the enclosure. For example, as will bedescribed in more detail below, a thermal pad 52 can be providedconfigured for contact with both the enclosure and the heat sink.

In some embodiments, a drive mounting system 10 can include one or moreheat sinks, one or more disk drives, and one or more shock absorbers.The one or more drive can be directly attached to the one or more heatsink and the one or more shock absorber is directly connected to the oneor more heat sink. One or more thermal conductor can be thermallyconnected to the one or more heat sink and configured to transfer heatfrom the one or more heat sink to an enclosure. The drive mountingsystem 10 can be part of a storage drive. The drive mounting system 10may further include one or more PCB and/or fan.

In some embodiments a storage drive can comprise two heat sinks and twoHDDs with four shock absorbers. The heats sinks can serve as mountingstructures for the HDDs. A thermal pad can be positioned on each of thetwo heat sinks. A PCB can be connected to the heat sinks with a fanconnected to the PCB. The fan can be positioned to direct air flowbetween the two HDDs.

Referring now to FIGS. 5A and 5B, a heat sink 50 can be seen in greaterdetail. The heat sink 50 can include one or more fins 54. In theillustrated embodiment the heat sink 50 has three fins 54. The one ormore fins 54 can extend from a base 56. As illustrated the fins extendperpendicular to the base, though it will be understood that they canextend at other angles.

The heat sink 50 can also include a number of mounting holes 58. Themounting holes 58 can be used to mount a drive 20, PCB 12, or otherdevice to the heat sink 50. The mounting holes 58 can be in the finsand/or base. As shown, the heat sink 50 has two pairs of mounting holes58 on the base 56 and one mounting hole 58 in the fin 54 at top. In thisembodiment, the two pairs of mounting holes on the base can be used toattach up to two drives to the heat sink and the mounting hole on thefin can be used to connect a PCB to the heat sink. It will be understoodthat any drive, PCB, or other device can be connected to the heat sinkin other ways such as with adhesive, snapfit, friction fit, etc.

The heat sink can define a number of mounting surfaces 59 at which thedrive, PCB, or other device can contact the heat sink. Having the drive,PCB, or other device in direct contact can allow the heat sink to drawheat from the drive, PCB, or other device to thereby help dissipate thatheat. A fan can also be used to help dissipate heat. The heat sink canbeneficially reduce the size of fan needed and/or the frequency of thefan turning on to cool the various components, among other benefits. Ashas been mentioned, the fan can be a significant draw on the power. Theheat sink can also increase the number and/or size of drives positionedin close relationship within a size efficient enclosure, including forportable devices.

In some embodiments, the heat sink 50 of the drive mounting system 10can be thermally connected to the enclosure. For example, a thermal pad52 (FIG. 6) can be provided that is configured for contact with both theenclosure and the heat sink. The thermal pad 52 is preferably athermally conductive elastomer. The thermal pad can be used to conductheat from the heat sink to the enclosure. In some embodiments, one ormore parts of the enclosure are made of metal, include metallicparticles, or are otherwise thermally conductive. The thermal pad 52 cantransfer heat from the heat sink to the enclosure. The enclosure canthen experience convection cooling. The system can also include a fan toprovide for internal convection cooling as well.

The thermal pad can be compliant so as to also provide shock absorptionand/or so that the heat sink is not rigidly coupled to the enclosure. Inother embodiments, that thermal connection can be provided by thermalgrease, conductive filler, etc. Preferably, the source of thermalconduction between the heat sink and the enclosure either provides someshock absorption or has minimal impact on the functioning of the shockabsorbers 16. For example, the thermal pad can be softer than the shockabsorbers. This flexibility can also be useful to help prevent bulgingof the lid of the enclosure.

The thermal pad can provide a thermally conductive interface. The padcan also be compliant. Viscoelastic compliance of the thermal pad whenattached to the heat sink with shock mounts can aid with shock andvibration isolation to the subassembly 22.

In some embodiments, at least one of the mating members (here the topmember 40) is metal, contains metal, thermally conductive plastic, or isotherwise thermally conductive. Preferably the majority of the enclosureis made of metal, contains metal, or is otherwise thermally conductive.In some embodiments, one, two, three, four, or more sides of theenclosure are made of metal, contain metal, or are otherwise thermallyconductive.

The heat sink 50 can also include a number of grooves 60 in a surface ofthe heat sink. As illustrated the grooves 60 are on a top surface of theheat sink 50. The grooves 60 can be used to increase the surface area ofthe heat sink 50. Looking to FIG. 6 it can be seen that the thermal pad52 can be forced into the space created by the grooves 60. This canincrease the amount of surface contact between the thermal pad 52 andthe heat sink 50.

In some embodiment, a heat sink can comprise a plurality of ridgesextending along a surface of a fin with a plurality of spaces or groovesbetween adjacent ridges. The thermal pad can be positioned along thissurface such that when fully assembled, the thermal pad is on at leastsome of the plurality of ridges and in at least some of the plurality ofspaces due to the force of the enclosure on the thermal pad, therebyincreasing the surface area of contact between the thermal pad and theheat sink.

Applicants' research has found that this increased surface area canincrease heat transfer. The thermal pad used on a heat sink with grooveshas been found to provide an additional 1-2 degrees Celsius (° C.) ofcooling compared to a similar device under the same conditions withoutthe grooves.

In some embodiments, it can be desirable for the thermal pad 52 toexperience at least 10% compression when the storage drive is in theassembled condition. For example, this can help ensure a sufficientthermal connection between the heat sink, the thermal pad and theenclosure (here the lid). This can also help ensure that the thermal padis positioned within the grooves on the heat sink. In some embodiments,the thermal pad 52 can be sized to experience a maximum of 15-20%compression. The load on the thermal pad can influence the pad's thermalimpedance. In some embodiments, the thermal pad can be sized toexperience between 10-20% compression when assembled. In otherembodiments, it can be greater than 5%, 7%, 8%, 10%, or 12%, but lessthan any of 13%, 15%, 17%, 20%, 22% and 25%.

Looking at cross-sections of FIGS. 2 and 6, one embodiment of the heatsink 50 within an enclosure can be seen. It can be seen that the drives20 and PCB 12 are sandwiched between two heat sinks 50. The drives 20and PCB 12 are in direct contact with the heat sink such that heat canflow from the drives and PCB to the heat sink. Heat can then flowthrough the thermal pad from the heat sink to the lid of the enclosure40.

In some embodiments, a heat sink can have a base having at least twomounting surfaces, each mounting surface configured for mounting each ofat least two drives to the heat sink; and a plurality of fins extendinggenerally perpendicularly from the base, at least one fin of theplurality of fins extending between two drives of the at least twodrive. The two heat sinks can be positioned on opposite sides of the atleast two drives. In some embodiments, at least one fin of the pluralityof fins of each of the two heat sinks that extends between the twodrives of the at least two drives, extends towards the respective fin ofthe other heat sink.

The size of the fins can be relatively short. This can allow forincreased air flow between the drives. For example, one or more of thefins can be shorter than 10%, 11%, 12%, 15%, and 17% of an overalllength a drive connected to the heat sink.

It will be understood that the devices connected to the heat sink 50 canbe stacked in any number of different orders. As shown, two drives 20are below a PCB 12. In other embodiments, a PCB can be below at leastone drive. In some embodiments the components can be stacked in order oftheir temperature rating, such that the component with the highestrating is on top. For example, many drives are rated for use at up to65° C., where many chips on a PCB may be rated for use at up to 80° C.Thus, the PCB can be on top. In some embodiments, the greatest heatgenerators can be on top. For example, a disk drive typically generatesmore heat than a PCB and more heat than other components that would bein a storage drive. Thus, the drives can be on top. It will beunderstood that the term “top” is a relative term and that a device mayhave feet on a side opposite the “top”. In some embodiments, there isnot a clearly defined top or bottom and/or the device can be configuredfor use in one of many different orientations.

As shown, a fin is positioned between each of the components on the heatsink. Each component can have a dedicated fin or can share fins. In someembodiment the heat sink does not have fins between each component.

FIG. 7 shows another embodiment of heat sink. This heat sink has fourfins, three large fins and one shorter fin. It will be understood thatany number and size of fins can be used. In the illustrated embodiment,up to three drives can be attached to the heat sink. A PCB can also beattached to the top of the heat sink.

According to some embodiments, a disk drive heat sink mounting structurecan be provided with integrated shock mounts to promote passive andforced convection cooling. The heat sink design can allow for mountingof multiple disk drives, a controller PCB and a pair of shock mounts,among other things.

A drive mounting system may be employed to enhance cooling ofcomponents, such as the controller electronics, SSD, and multiple diskdrives densely stacked inside an enclosure, and also providing shock andvibration isolation. In some embodiments, the drive mounting system canbe used bus-powered devices, such as a THUNDERBOLT-powered devices andUSB-powered devices.

In some embodiments, the heat sink can perform multiple functions, bothstructural and thermodynamic. It can be used as a heat dissipating (heatconducting medium) element and it can be used as the key mechanicalmounting structure for storage drives, such as HDDs, and the requiredcircuit boards. The storage drive of some embodiments preferablyprovides sufficient sway space around the disk drive subassembly foreffective shock and vibration isolation, yet also provides asufficiently effective heat conductive path between the heat sink andthe outer enclosure.

According to some embodiments, a storage device can comprise at leasttwo drives, first and second mating members that when engaged form anenclosure, two heat sinks for mounting the two drives within theenclosure, and a plurality of shock absorbers. Each heat sink cancomprise a base having at least two mounting surfaces, each mountingsurface configured for mounting each of the at least two drives to theheat sink; and a plurality of fins extending generally perpendicularlyfrom the base, at least one fin of the plurality of fins extendingbetween two drives of the at least two drives. Each of the shockabsorbers can be connected to one of the two heat sinks and theenclosure to isolate the at least two drives from the enclosure. Each ofthe two heat sinks can be thermally connected to the enclosure and tothe at least two drives such that heat from the at least two drives istransferred from the at least two drives to the heat sinks and then tothe enclosure.

The storage device can further include two thermal pads where eachthermal pad is in contact with one of the two heat sinks and theenclosure to thermally connect the respective heat sink to theenclosure. One of the plurality of fins of each of the two heat sinkscan have a plurality of ridges extending along a surface of the fin witha plurality of spaces between adjacent ridges. The thermal pad can bepositioned along said surface such that when fully assembled, thethermal pad is on at least some of the plurality of ridges and in atleast some of the plurality of spaces due to the force of the enclosureon the thermal pad, thereby increasing the surface area of contactbetween the thermal pad and the heat sink.

The two heat sinks can be positioned on opposite sides of the at leasttwo drives. Further, the at least one fin of the plurality of fins ofeach of the two heat sinks that extends between the two drives of the atleast two drives can extend towards the respective fin of the other heatsink. The at least one fin of the plurality of fins of each of the twoheat sinks can be shorter than 10%, 12%, or 15% of an overall length ofeither of the two drives of the at least two drives, thereby allowingairflow between the two drives of the at least two drives.

In some embodiments, a storage device can comprise at least two drives,first and second mating members that when engaged form an enclosure, aheat sink for mounting the at least two drives within the enclosure, anda plurality of shock absorbers connected to the heat sink and theenclosure to isolate the at least two drives from the enclosure. Theheat sink can include a base having at least two mounting surfaces, eachmounting surface configured for mounting each drive of the at least twodrives to the heat sink; and a fin extending generally perpendicularlyfrom the base and between two drives of the at least two drives. Theheat sink can be thermally connected to the enclosure and to the atleast two drives such that heat from the at least two drives istransferred from the drives to the heat sink and then to the enclosure.

The storage device may include a second heat sink, where each heat sinkis positioned on opposite sides of the at least two drives. A thermalpad can be in contact with the heat sink and the enclosure to thermallyconnect the heat sink to the enclosure. The heat sink can furthercomprise a plurality of ridges extending along a surface of the fin witha plurality of spaces between adjacent ridges, the thermal padpositioned along said surface such that when fully assembled, thethermal pad is on at least some of the plurality of ridges and in atleast some of the plurality of spaces due to the force of the enclosureon the thermal pad, thereby increasing the surface area of contactbetween the thermal pad and the heat sink.

According to some embodiments, a heat sink for stacking multiple drivescan comprise a base having first and second mounting surfaces, onesurface for mounting each of two drives to the heat sink; and first,second and third fins extending generally perpendicularly from the base.The first and second fins can be spaced to allow a printed circuit board(PCB) to be mounted between them on the heat sink. The second and thirdfins can be spaced to allow a first drive to be mounted between them onthe heat sink at the first mounting surface, and a second drive to bemounted adjacent only the third fin at the second mounting surface. Thefirst fin can comprise a plurality of ridges extending along a surfaceof the first fin with a plurality of spaces between adjacent ridges.

A thermal pad can be positioned on at least some of the plurality ofridges and in at least some of the plurality of spaces.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. Thus, it is intended that the scope ofthe present invention herein disclosed should not be limited by theparticular disclosed embodiments described above.

Similarly, this method of disclosure, is not to be interpreted asreflecting an intention that any claim require more features than areexpressly recited in that claim. Rather, as the following claimsreflect, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment. Thus, the claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment.

What is claimed is:
 1. A storage device comprising: at least two drives;first and second mating members that, when engaged, form an enclosure;two heat sinks for mounting the at least two drives within theenclosure, each heat sink comprising: a base having at least twomounting surfaces, each mounting surface configured for mounting one ofthe at least two drives to the heat sink; and a plurality of finsextending generally perpendicularly from the base, at least one fin ofthe plurality of fins extending between two drives of the at least twodrives; and four shock absorbers, each shock absorber connected to oneof the two heat sinks and the enclosure to isolate the at least twodrives from the enclosure; wherein each of the two heat sinks arethermally connected to the enclosure and to the at least two drives suchthat heat from the at least two drives is transferred from the at leasttwo drives to the heat sinks and then to the enclosure.
 2. The storagedevice of claim 1, further comprising two thermal pads, each thermal padin contact with one of the two heat sinks and the enclosure to thermallyconnect the respective heat sink to the enclosure.
 3. The storage deviceof claim 2, wherein one of the plurality of fins of each of the two heatsinks comprises a plurality of ridges extending along a surface of thefin with a plurality of spaces between adjacent ridges, the thermal padpositioned along said surface such that when fully assembled, thethermal pad is on at least some of the plurality of ridges and in atleast some of the plurality of spaces due to the force of the enclosureon the thermal pad, thereby increasing the surface area of contactbetween the thermal pad and the heat sink.
 4. The storage device ofclaim 1, wherein the two heat sinks are positioned on opposite sides ofthe at least two drives.
 5. The storage device of claim 4, wherein theat least one fin of the plurality of fins of each of the two heat sinksthat extends between the two drives of the at least two drives, extendstowards the respective fin of the other heat sink.
 6. The storage deviceof claim 5, wherein the at least one fin of the plurality of fins ofeach of the two heat sinks is shorter than 15% of an overall length ofeither of the two drives of the at least two drives, thereby allowingairflow between the two drives of the at least two drives.
 7. Thestorage device of claim 1, wherein each fin of the plurality of fins ofeach of the two heat sinks is shorter than 15% of an overall length ofeither of the two drives of the at least two drives, thereby allowingairflow between the two drives of the at least two drives.
 8. Thestorage device of claim 1, wherein the plurality of fins on each heatsink comprises three fins on each of the two heat sinks.
 9. The storagedevice of claim 8, further comprising a printed circuit board (PCB)mounted on the two heat sinks adjacent one of the two drives of the atleast two drives and between two of the three fins on each of the twoheat sinks.
 10. The storage device of claim 9, wherein one of the twodrives of the at least two drives is mounted on the two heat sinks withthe PCB on one side of the one of the two drives and the other of thetwo drives on the opposite side of the one of the two drives and beingbetween two of the three fins on each of two heat sinks.
 11. The storagedevice of claim 1, wherein each of the at least two drives is not indirect contact with the enclosure.
 12. The storage device of claim 1,wherein each of the at least two mounting surfaces comprises a pair ofmounting holes.
 13. A storage device comprising: at least two drives;first and second mating members that, when engaged, form an enclosure; aheat sink for mounting the at least two drives within the enclosure, theheat sink comprising: a base having at least two mounting surfaces, eachmounting surface configured for mounting one drive of the at least twodrives to the heat sink; and a fin extending generally perpendicularlyfrom the base and between two drives of the at least two drives; and aplurality of shock absorbers connected to the heat sink and theenclosure to isolate the at least two drives from the enclosure; whereinthe heat sink is thermally connected to the enclosure and to the atleast two drives such that heat from the at least two drives istransferred from the drives to the heat sink and then to the enclosure.14. The storage device of claim 13, further comprising a second heatsink, wherein each heat sink is positioned on opposite sides of the atleast two drives.
 15. The storage device of claim 13, further comprisinga thermal pad in contact with the heat sink and the enclosure tothermally connect the heat sink to the enclosure.
 16. The storage deviceof claim 15, wherein the heat sink further comprises a plurality ofridges extending along a surface of the fin with a plurality of spacesbetween adjacent ridges, the thermal pad positioned along said surfacesuch that when fully assembled, the thermal pad is on at least some ofthe plurality of ridges and in at least some of the plurality of spacesdue to the force of the enclosure on the thermal pad, thereby increasingthe surface area of contact between the thermal pad and the heat sink.17. The storage device of claim 16, wherein the heat sink furthercomprises a second fin extending generally perpendicularly from thebase, wherein the plurality of ridges are on the second fin.
 18. A heatsink for stacking multiple drives, the heat sink comprising: a basehaving first and second mounting surfaces, one surface for mounting eachof two drives to the heat sink; and first, second and third finsextending generally perpendicularly from the base, wherein: the firstand second fins are spaced to allow a printed circuit board (PCB) to bemounted between them on the heat sink, the second and third fins arespaced to allow a first drive to be mounted between them on the heatsink at the first mounting surface, and a second drive to be mountedadjacent only the third fin at the second mounting surface, and thefirst fin comprises a plurality of ridges extending along a surface ofthe first fin with a plurality of spaces between adjacent ridges. 19.The heat sink of claim 18, further comprising a thermal pad positionedon at least some of the plurality of ridges and in at least some of theplurality of spaces.
 20. The heat sink of claim 18, wherein at least oneof the first, second and third fins is shorter than an overall length ofat least one of the first and second drives, thereby allowing airflow bythe at least one of the first and second drives.